Abstract:

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We synthesized barium titanate (BaTiO3) nanoparticles by sol-gel process and investigated their
crystallization behavior using differential scanning calorimetry and X-ray diffraction. BaTiO3
nanoparticles with various degrees of crystallinity were obtained by adjusting synthesis conditions.
Under aging conditions that do not allow dealcholization reaction to complete, many hydroxyl
ligands remain in as-synthesized BaTiO3 nanoparticles, resulting in the formation of voids or
defects in the nanoparticles after calcination. It is essential to use high concentration alkoxides
precursor solutions for producing BaTiO3 nanoparticles with high crystallinity at low temperature.

Abstract: BaNd2Ti4O12 dielectric oxide particles were spheroidized by melting them with a LPG-O2 flame to improve packing and fluidity of the powder. Changes in the particle morphology, structure and crystallinity during the process were investigated. It is revealed that most of the as-melted particles are dense, spherical and amorphous with smooth surfaces, which crystallize in the annealing process to form polycrystalline spherical particles with uneven surfaces. Annealing at above 1100°C is necessary for the spheroidized powder to recover its crystallinity and dielectric properties.

Abstract: Bi-2212 superconducting phase was synthesized via sol-gel method, and the experimental parameters such as the concentration of precursor solution and heat treatment temperature were adjusted to find the optimal conditions. Metal nitrates were adopted as the starting materials and ethylenediaminetetracetic acid (EDTA) as chelating agent. Precursor solutions and gel with different concentration were obtained through the addition of different content of distilled water as solvent followed by heating at certain temperature to form grey powders. Afterwards, the powders were sintered at different temperature for 10 hours, respectively. X-ray diffraction (XRD) was adopted to investigate the phase purity and crystallinity of the sample derived. Results reveal that the optimized precursor solution concentration is 27% and the optimized sintering temperature is 850°C.

Abstract: For prepare magnetic liquids with good property, the authors prepared Magnetic Fe3O4 nanoparticles by co-precipitation in different temperatures including 60°C, 70°C, 80°C in this experiment and analyzed the product of Magnetic Fe3O4 nanoparticles by X-ray Diffraction Analysis, Transmission Electron Scanning, Saturation Magnetization Test and the result indicate that Magnetic Fe3O4 nanoparticles prepared at 70°C have good crystallinity and high saturation magnetization and suitable for prepare magnetic liquid.

Abstract: N-doped mesoporous TiO2 with high surface area and crystallinity were synthesized by sol-gel method using polyacrylamide (PAM) and polyethylene glycol (PEG) as the complex templates. The resulting materials were characterized by XRD, TEM, N2 adsorption-desorption, and UV-Vis spectroscopy. It is found that when the weight ratio of PAM and PEG is 1:4, the sample, prepared at 600 °C in nitrogen and at 500 °C in air, is anatase phase and has high surface area and crystallinity. The particle size and pore size of the sample are about 10 nm and 17 nm respectively. Compared with that of the undoped mesoporous TiO2, the absorption band edges of N-doped samples exhibit an evident red-shift. The results of the photocatalytic degradation of methyl orange (MO) show that N-doped sample appears to have higher photocatalytic activity under visible light than undoped sample.